PrepZii

table

Group 1, Group 2 and Hydration

The s-block section opens with group membership and hydration trends.

Members

Group	Elements listed
Group 1	Li, Na, K, Rb, Cs and Fr
Group 2	Be, Mg, Ca, Sr, Ba and Ra

Hydration

Ions	Source-backed trend
Alkali metal ions	Hydration enthalpies decrease with increase in ionic size; $Li^+$ has maximum hydration.
Alkaline earth metal ions	$Be^{2+}>Mg^{2+}>Ca^{2+}>Sr^{2+}>Ba^{2+}$ .
Group comparison	Alkaline earth metal ion hydration enthalpies are larger than alkali metal ion hydration enthalpies.